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Age problems |
| Example:
A father is 48 years old
and his son is 14. |
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a) In how many years will the father be three times older
then his son? |
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b) How many years before was the father seven times older
then his son? |
| Solution:
After x
years a) 48
+ x = 3 ·
(14 + x) |
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48 + x = 42 + 3x |
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x -
3x = 42 -
48 |
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-2x
= -6
| ¸
(-2) |
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x = 3 years. |
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Before x
years b) 48
-
x = 7 · (14 -
x) |
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48 -
x = 98 -
7x |
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7x -
x = 98 -
48
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6x = 50
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x = 25/3 = 8 years and 4
months.
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Miscellaneous word
problems
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Example:
If fresh grapes contain 90% water and dried 12%, how much dry grapes we get from 22 kg of fresh
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grapes?
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Solution: Fresh grapes contain 90% water and 10% dry substance.
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Dry grapes contain 12% water and 88% dry substance.
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| 22 kg of fresh grapes = x kg
of dry grapes, so |
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Example: An amount decreased 20% and then increased 50%, what is the total increase in relation to initial
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value.
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Solution: An initial amount
x decreased by 20%, |
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The obtained amount increased by 50%, |
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The difference in relation to the initial value x,
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shows increase by 20%.
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Example: From a total deducted is 5% for expenses and the remainder is equally divided to three persons.
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What was the total
if each person gets $190?
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Solution: If
x
denotes the total then |
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Example: Into 10 liters of the liquid
A poured is 4 liters of the liquid
B
and 6 liters of the liquid
C.
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From obtained mixture D
poured is out 3 liters, how many liters of the liquid C
remains in the mixture
D?
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Solution: A
+ B
+ C
= D
=> 10 l + 4 l + 6 l = 20 l
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| Intermediate
algebra contents |
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| Copyright
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